JPH0714438B2 - Cloth cutting device for buttonhole sewing machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cloth cutting device for a buttonhole overedging machine, and more particularly, to the completion of a buttonhole overedging stitch forming cycle in conjunction with the upper shaft of the sewing machine. In a cloth cutting device that automatically cuts buttonholes in a cloth, the sewing machine is designed to prevent the automatic cutting of buttonholes when the sewing machine is driven at high speed in connection with the completion of a buttonhole stitch forming cycle. The present invention relates to a cloth cutting device.

[Prior Art] FIG. 2 is a perspective view of a main part of a conventional cloth cutting device in a buttonhole overedging machine.

In the figure, reference numeral 1 is a drive lever pivotally supported by a shaft 1a, which is provided at one end with a knife plate 4 having a cloth cutting knife 5 at the bottom thereof, and at the other end thereof is supported by a knife drive hook 3 as an engaging body. A spring (not shown) is always provided with an acting force for keeping the knife 5 upward.

The knife drive hook 3 as an engaging body is provided with an engaging portion 3a as a concave portion that engages with a swinging body 2 described later at the upper end thereof, and is normally urged to rotate clockwise by a spring 3b.

Reference numeral 2 denotes a female driving arm as an oscillating body, which is constantly moved up and down in the arrow A direction in conjunction with the upper shaft.

6 is a starting rod that operates the starting arm 8 in conjunction with a starting frame of a sewing machine (not shown), 7 is a push rod that moves up and down by a cam (not shown) that rotates in conjunction with the upper shaft on the bottom surface of the sewing machine bed, and 9 is This is an operation cam device that rotates the knife drive hook 3 as the push rod 7 moves up and down.

The starting arm 8 is engaged with the pin 3c of the knife driving hook 3 to prevent its rotation when the sewing machine is stopped.

Next, the operation of the conventional cloth cutting device configured as described above will be described.

When the sewing machine is driven, the starting rod 6 that interlocks with the starting frame (not shown) moves in the direction of arrow B, and the starting arm 8 moves along the axis.
It rotates counterclockwise around 8a, and the engagement with the pin 3c of the knife driving hook 3 is released.

Then, the projection 3d of the knife driving hook 3 engages with the actuating cam mechanism 9, and the actuating cam mechanism 9 operates to turn it. In this state, when the buttonhole overlocking proceeds, and shortly before its completion, the push rod 7 is moved up and down by a cam (not shown) interlocking with the upper shaft.

By the operation of the operation cam mechanism 9, the knife driving hook 3 is rotated clockwise about the shaft 3e by the rotational biasing force of the spring 3b, and the engaging portion 3a is engaged with the vertically moving tip of the knife driving arm 2. .

As a result of the knife driving hook 1 swinging around the shaft 1a, the cloth cutting knife 5 moves up and down to cut a predetermined portion of the cloth and form the button hole almost at the same time when the button hole overlock is completed.

By the way, the driving of the sewing machine in the buttonhole sewing is started at a low speed at the beginning of sewing, then becomes a high speed, and then becomes a low speed again to complete one cycle. Then, as described above, the operation of the cloth cutting knife, that is, the engagement between the engaging portion of the knife driving hook and the knife driving arm swinging in conjunction with the upper shaft,
Immediately before the end of buttonhole stitching, the sewing machine is automatically driven by the operation of the cam that is interlocked with the upper shaft while the sewing machine is driven at a low speed.

[Problems to be Solved by the Invention] However, in the above-described conventional cloth cutting apparatus, as described above, the sewing machine is driven at a high speed or at a low speed in accordance with the end of the buttonhole stitching cycle. The cloth cutting knife automatically operates regardless of whether it is driven.

For this reason, even if the sewing machine is in a high-speed driving state during the operation of the cloth cutting knife before the end of the buttonhole sewing for some reason, the cloth cutting knife and the knife driving arm are engaged with each other.

When the sewing machine is driven at high speed, the swinging of the knife driving arm interlocked with the upper shaft is also at high speed. Therefore, when trying to engage the knife drive hook and the knife drive arm in this state,
An abnormal noise or a breakage accident may occur due to overload on each related member. Furthermore, in the above-mentioned conventional cloth cutting device, since the cloth cutting is always operated every one cycle of buttonhole overedging, the buttonhole overdoo
In order to sew once or three times, it is necessary to replace parts such as cams, which not only lowers productivity but also raises cost and cost.

[Means for Solving Problems] The present invention relates to a link device that interlocks with a starting frame through a transmission rod in a cloth cutting device, and an engagement pin whose tip portion is provided on the engagement body when the sewing machine is driven at a low speed. When the sewing machine is stopped and driven at high speed, the safety rod is rotated and biased so as to be separated from and opened from the safety rod, and the safety rod is rotated against the rotation biasing force to engage the tip of the safety rod. An object of the present invention is to solve the above-mentioned conventional problems by providing a safety rod operating mechanism that engages with the engaging pin of the united body.

[Operation] The safety rod is normally urged to rotate so that the tip of the safety rod separates from the engagement pin provided on the engagement body.

On the other hand, the link mechanism that interlocks with the sewing machine start frame,
The safety rod is engaged with the engaging body through the safety rod actuating mechanism when the driving of the sewing machine is stopped and at high speed to prevent the engagement of the engaging body and the rocking body.

Therefore, when the sewing machine is driven at a low speed, the engagement body and the oscillating body can be engaged according to a predetermined operation, and when the sewing machine is driven at a high speed, the safety rod is locked to the engagement body even if a predetermined operation is performed to operate the engagement body. Therefore, the engagement between the engaging body and the rocking body, that is, the operation of the cloth cutting knife is prevented.

[Embodiment] An embodiment of the present invention will be described with reference to the drawings. The same parts as those in the conventional example are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 1 is a perspective view of an essential part showing an embodiment of a cloth cutting device according to the present invention.

In the figure, reference numeral 21 is a transmission rod which is interlocked with a sewing machine starting frame (not shown), and 22 is a first arm which is axially supported by the end portion of the transmission rod 21 and whose tip is fixed to a shaft 22a.

The lower end of 23 is fixed to the shaft 2a and the leading end of the plate 24 is
Is a second arm pivotally supported at one end of the. A long hole 24a is formed at the other end of the plate 24, and the tip of a third arm 25 described later is
It is pivoted at 4b.

The lower end of the third arm 25 is axially supported by a shaft 30 coaxially with one end of a first operation plate 29, which will be described later, while a protrusion 25a is formed on the lower end side portion.

First arm 22, second arm 23, plate 24, third arm
25 forms a link mechanism.

Reference numeral 26 is a second plate which is rotatably supported by a shaft 28 and is horizontally rotatable. One end of the second plate abuts on the inner side of the plate 24, and the other end thereof has one end of an engaging rod 27. It is supported. The other end of the engaging rod 27 is pivotally supported on the tip of the first operating plate 29.

A protrusion 29a is provided on the upper outer end of the first operating plate 29 so as to abut the protrusion 25a at a predetermined position, while the lower end of the first operating plate 29 is pivotally supported on one end of the third operating plate 32. Has been done.

The other end of the third operating plate 32 has a safety rod 31.
Is pivotally supported at the center end of the. Second operating plate 26, engagement rod 27, first operating plate 29, third operating plate 32
The safety rod actuating mechanism is constituted by.

The lower end of the safety rod 31 attached to the knife driving hook 3 is axially supported, and the upper end of the safety rod 31 is constantly urged to rotate clockwise by a spring (not shown) and receives a predetermined actuating force. It is adapted to come into contact with an engagement pin 33 fixedly provided on the upper portion.

The operation of the embodiment will be described with the above configuration.

FIG. 1 shows a state where the driving of the sewing machine is stopped and the safety rod 31 is in contact with the engagement pin 33. At this time,
The second working plate 26 is separated from the inner surface of the plate 24.

Further, the protrusion 25a and the protrusion 29a are engaged with each other, and prevent the safety rod 31 from being rotated clockwise by the biasing force of the spring and being disengaged from the engagement pin 33.

When the starting frame is set to the low speed position and the driving of the sewing machine is started, the transmission rod 21 moves in the arrow direction by a predetermined amount.

Then, the second arm 23, the plate 24, and the third arm 25 are
Each of them rotates counterclockwise via the first arm 22.
Therefore, the engagement between the protrusion 25a and the protrusion 29a is released.

Therefore, the safety rod 31 is rotated clockwise by the urging force of the spring to release the engagement with the engagement pin 33, and the knife drive hook 3 is ready to be engaged with the knife drive arm 2.

It should be noted that with the clockwise rotation of the safety rod 31, the first
The actuating plate 29 rotates counterclockwise about the shaft 30 and rotates the second actuating plate 26 via the engaging rod 27 so that the tip end portion of the actuating plate 29 is brought into contact with the inner surface of the plate 24.

Next, when the activation frame is set at high speed, the transmission rod
21 moves further in the arrow direction than at the time of low speed.

Then, the second arm 23 rotates counterclockwise via the first arm 22 and rotates the second operation plate 26 that is in contact with the inside of the plate 24.

Therefore, in this state, even if the actuating cam mechanism 9 is actuated by the vertical movement of the push rod 7 and the knife driving hook 3 is rotated clockwise by the urging force of the spring 3b, the knife driving hook 3 will not move. As a result, the engagement with the knife driving arm 2 is blocked, and the cloth cutting knife 5 does not operate.

When the driving of the sewing machine is stopped, the transmission rod 21 moves in the direction opposite to the arrow.

Along with this, the second arm 23, the plate 24, and the third arm 25 rotate clockwise via the first arm 22, respectively.

As a result, the protrusion 25a abuts the protrusion 29a to rotate the first actuation plate 29 clockwise, and as a result, the safety rod 31 is turned counterclockwise via the third actuation plate 32 to engage. Engage with pin 33.

[Effects of the Invention] According to the present invention, when the sewing machine is driven at a high speed, the engagement of the engaging body with the oscillating body is blocked by the safety rod. When the sewing machine does not shift from the high-speed drive state to the low-speed drive state at the end of one sewing cycle, engagement of the engagement body with the oscillating body is prevented, so that abnormal noise is generated due to engagement during high-speed drive. No inconvenience such as breakage of related members occurs.

Further, if the high-speed drive of the sewing machine is maintained immediately before the completion of one cycle of buttonhole sewing, the cloth cutting knife does not operate, so there is an effect that double stitching of buttonhole stitching, triple stitching, etc. can be properly performed. .

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a cloth cutting mechanism according to the present invention, and FIG. 2 is a perspective view of a main part of the conventional cloth cutting mechanism. 1 ... Drive lever 2 ... Oscillating body 3 ... Engaging body 22 ... First arm 23 ... Second arm 24 ... Plate 25 ... Third arm 26 ... Second operating plate 27 ... Engaging rod 29 …… First actuation plate 32 …… Third actuation plate 31 …… Safety rod

Claims (1)

[Claims] 1. A knife plate 4 which has a cloth cutting knife 5 and which is supported on the machine frame so as to be movable up and down, is connected to one end thereof, and is always rotated by the machine frame so as to receive an acting force for moving the knife plate 4 upward. A drive lever 1 movably supported, an oscillating body 2 rotatably supported by the machine frame so as to oscillate in conjunction with the sewing machine mechanism, and a lower end rotatably supported by the other end of the drive lever 1. , An engaging portion 3a engageable with the rocking body 2 is formed at the upper end,
3a and an oscillating body 2 are engaged with each other, the drive lever 1 is oscillated against the acting force of the oscillating body 2 to move the cloth cutting knife 5 up and down. In a cloth cutting device for a buttonhole overedging machine that enables engagement between the engaging portion 3a of the united body 3 and the oscillating body 2, a transmission rod 21 connected to a starting frame for changing the driving speed of the sewing machine according to its moving position, A second arm 23 that is connected to the rod 21 via a first arm 22 and swings around a shaft 22a provided at the lower end in conjunction with the movement of the transmission rod 21, and is rotatable to the upper end of the second arm 23. The plate 24 and the machine frame rotatably support the middle part, and the upper end is connected to the plate 24 through the long hole 24a and the pin inserted into the long hole, and the projection 25a is formed at the lower end. 3 The arm 25 and the machine frame rotatably support the middle part, The first force that is always applied by the elastic force in the direction of engaging the protrusion 25a
The operating plate 29 and the lower end are rotatably supported by the sewing machine frame, and the intermediate portion is connected to the first operating plate 29. The elastic force always urges the oscillating body 2 to rotate and the upper end portion is urged. The rocking body 2 of the engaging body 3 is arranged so as to face the pin 33 formed at the tip of the engaging body 3.
The safety rod 31 for allowing and prohibiting rotation in the direction and the middle portion of the sewing machine frame are rotatably supported, one end is engaged with the second arm 23, and the other end is connected with the upper end of the first operation plate 29. The second actuating plate 26 moves the safety rod 31 in the direction of the oscillating body 2 in conjunction with the movement of the starting frame by a predetermined amount when the sewing machine operates at a low speed to engage the engaging body 3 with the oscillating body 2. The operation of the cloth cutting knife 5 is allowed, and by further movement of the starting frame of the sewing machine at high speed, the second operating plate 26 is rotated to move the safety rod 31 in the direction separating from the rocking body 2, A cloth cutting device for a buttonhole overlock sewing machine, characterized in that the engagement between the united body 3 and the oscillating body 2 is prevented and the operation of the cloth cutting knife 5 is prevented.